Remove uses of std::unary_function and std::binary_function.

components/variations/entropy_provider.h

Index: components/variations/entropy_provider.h
diff --git a/components/variations/entropy_provider.h b/components/variations/entropy_provider.h
index fa7a1e25610ccaff49efa8a1bd517684bc6177cc..27e73eb3564e41ee5c6234c39dadb9b49673eea6 100644
--- a/components/variations/entropy_provider.h
+++ b/components/variations/entropy_provider.h
@@ -24,7 +24,7 @@ namespace internal {
 
 // A functor that generates random numbers based on a seed, using the Mersenne
 // Twister algorithm. Suitable for use with std::random_shuffle().
-struct SeededRandGenerator : std::unary_function<uint32_t, uint32_t> {
+struct SeededRandGenerator {
   explicit SeededRandGenerator(uint32_t seed);
   ~SeededRandGenerator();